The CTFPHC updates its 2001 recommendations based on the
most recent data available in its February 22nd CMAJ online
report.

For adults aged 60 to 74, the task force strongly recommends
screening for CRC with gFOBT or FIT every two years or flexible
sigmoidoscopy every 10 years, based on moderate-quality
evidence. A weak recommendation based on moderate-quality
evidence supports similar screening of adults aged 50 to 59.

The task force weakly recommends against screening adults
aged 75 years and older for CRC based on low-quality evidence
showing no improvement in CRC mortality or morbidity in this age
group.

The weak recommendation against colonoscopy as a primary
screening test for CRC is also based on low-quality evidence.
"Although colonoscopy may offer clinical benefits that are
similar to or greater than those associated with flexible
sigmoidoscopy, direct evidence of its efficacy in comparison
with the other screening tests (in particular FIT) is lacking,"
the authors note.

They also cite lengthy wait lists for colonoscopy and
insufficient gastroenterologists in Canada as arguments against
routine colonoscopy for CRC screening.

"Regardless of age, primary care providers should discuss
the most appropriate choice of test with patients who are
interested in screening, considering patient values and
preferences as well as local test availability," the
recommendations conclude.

Dr. Robert Smith, American Cancer Society (ACS) Vice
President for Cancer Screening, Atlanta, Georgia, told Reuters
Health, "In the U.S. the advantage of colonoscopy was judged to
be clear in spite of the absence of data from a prospective
randomized controlled trial, and early on the ACS and U.S.
Multi-Society Task Force endorsed screening colonoscopy every 10
years, and eventually the USPSTF did also. However, the U.S.
guidelines also see greater advantage from annual stool testing
vs. stool testing every other year, consistent with the stronger
data from the Minnesota Trial."

"We're still learning about long term outcomes associated
with flexible sigmoidoscopy, but it should be recognized that
deaths prevented are limited to the cancers that arose in the
distal colon," he explained. "That is one reason why it has
fallen out of favor in the U.S., along with weak incentives for
its use in the primary care setting."

"New data also show very clearly that a substantial fraction
of adults are not willing to undergo colonoscopy and thus
recommendations to get a colonoscopy in this group will go
unheeded," Dr. Smith said. "The data also show that many of
these adults will accept stool testing, and thus achieving high
rates of colorectal cancer screening in the practice setting
requires providing at least the option for colonoscopy or,
ideally, a high sensitivity FIT."

"If a practice is still using the old Hemoccult tests, they
should stop and replace them with either a high sensitivity
guaiac test (i.e., Hemoccult SENSA) or a high sensitivity FIT,"
he said. "FIT is more patient friendly, more likely to be
completed, and tends to have overall better accuracy. High
sensitivity stool testing should not be judged as an inferior
test to colonoscopy, especially for a patient who will not get
screened if colonoscopy is the only option."

Dr. Smith concluded, "We have a saying.the best test for
colorectal cancer screening is the one that gets done."